" Copyright 2011 The Go Authors. All rights reserved.
" Use of this source code is governed by a BSD-style
" license that can be found in the LICENSE file.
"
" indent/go.vim: Vim indent file for Go.
"
" TODO:
" - function invocations split across lines
" - general line splits (line ends in an operator)

if exists("b:did_indent")
    finish
endif
let b:did_indent = 1

" C indentation is too far off useful, mainly due to Go's := operator.
" Let's just define our own.
setlocal nolisp
setlocal autoindent
setlocal indentexpr=GoIndent(v:lnum)
setlocal indentkeys+=<:>,0=},0=)

if exists("*GoIndent")
    finish
endif

function! GoIndent(lnum)
    let prevlnum = prevnonblank(a:lnum-1)
    if prevlnum == 0
        " top of file
        return 0
    endif

    " grab the previous and current line, stripping comments.
    let prevl = substitute(getline(prevlnum), '//.*$', '', '')
    let thisl = substitute(getline(a:lnum), '//.*$', '', '')
    let previ = indent(prevlnum)

    let ind = previ

    if prevl =~ '[({]\s*$'
        " previous line opened a block
        let ind += &sw
    endif
    if prevl =~# '^\s*\(case .*\|default\):$'
        " previous line is part of a switch statement
        let ind += &sw
    endif
    " TODO: handle if the previous line is a label.

    if thisl =~ '^\s*[)}]'
        " this line closed a block
        let ind -= &sw
    endif

    " Colons are tricky.
    " We want to outdent if it's part of a switch ("case foo:" or "default:").
    " We ignore trying to deal with jump labels because (a) they're rare, and
    " (b) they're hard to disambiguate from a composite literal key.
    if thisl =~# '^\s*\(case .*\|default\):$'
        let ind -= &sw
    endif

    return ind
endfunction

" vim:sw=4:et
